Vehicular tires, particularly pneumatic tires, are sometimes provided with a component such as, for example, a tread which is comprised of a rubber composition which contains two or more rubbers or elastomers.
Elastomer blends which contain, for example, cis 1,4-polybutadiene and styrene/butadiene elastomers are often used for such tire component (e.g. tire tread). Rubber compositions may also contain various amounts of additional diene-based elastomers such as, for example, one or more of cis 1,4-polyisoprene, cis 1,4-polybutadiene, medium vinyl polybutadiene, styrene/butadiene copolymers, isoprene/butadiene copolymers, and minor amounts of 3,4-polyisoprene.
For the above mentioned styrene/butadiene copolymer rubber, both emulsion polymerization prepared and organic solvent polymerization prepared styrene/butadiene copolymer elastomers have been used. Also, historically, emulsion polymerization derived copolymer elastomers comprised of units derived from styrene and 1,3-butadiene together with an additional monomer have been prepared and proposed for use for various products.
U.S. Pat. No. 5,902,852 discloses the modification of an asphalt cement with a rubbery copolymer prepared by emulsion polymerization which is comprised of repeat units derived from conjugated diolefin monomer, such as, for example, cis 1,4-polybutadiene, vinyl aromatic monomer such as styrene and a small amount of hydroxypropyl methacrylate (HPMA).
U.S. Pat. No. 6,057,397 discloses use of a copolymer of cis 1,4-polybutadiene, styrene and, for example hydroxypropyl methacrylate in rubber compositions.
Hydroxy-containing polymers are disclosed in U.S. Pat. Nos. 4,150,014, 4,150,015, 4,152,308 and 4,357,432.
U.S. Pat. No. 6,716,925 discloses use of a hydroxy-containing rubber with a rubber containing a nitrile moiety.